<?php
namespace TYPO3\CMS\Core\Utility;

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

use TYPO3\CMS\Frontend\Page\PageRepository;

/**
 * A utility resolving and Caching the Rootline generation
 */
class RootlineUtility
{
    /**
     * @var int
     */
    protected $pageUid;

    /**
     * @var string
     */
    protected $mountPointParameter;

    /**
     * @var array
     */
    protected $parsedMountPointParameters = array();

    /**
     * @var int
     */
    protected $languageUid = 0;

    /**
     * @var int
     */
    protected $workspaceUid = 0;

    /**
     * @var bool
     */
    protected $versionPreview = false;

    /**
     * @var \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface
     */
    protected static $cache = null;

    /**
     * @var array
     */
    protected static $localCache = array();

    /**
     * Fields to fetch when populating rootline data
     *
     * @var array
     */
    protected static $rootlineFields = array(
        'pid',
        'uid',
        't3ver_oid',
        't3ver_wsid',
        't3ver_state',
        'title',
        'alias',
        'nav_title',
        'media',
        'layout',
        'hidden',
        'starttime',
        'endtime',
        'fe_group',
        'extendToSubpages',
        'doktype',
        'TSconfig',
        'tsconfig_includes',
        'is_siteroot',
        'mount_pid',
        'mount_pid_ol',
        'fe_login_mode',
        'backend_layout_next_level'
    );

    /**
     * Rootline Context
     *
     * @var \TYPO3\CMS\Frontend\Page\PageRepository
     */
    protected $pageContext;

    /**
     * @var string
     */
    protected $cacheIdentifier;

    /**
     * @var array
     */
    protected static $pageRecordCache = array();

    /**
     * @var \TYPO3\CMS\Core\Database\DatabaseConnection
     */
    protected $databaseConnection;

    /**
     * @param int $uid
     * @param string $mountPointParameter
     * @param \TYPO3\CMS\Frontend\Page\PageRepository $context
     * @throws \RuntimeException
     */
    public function __construct($uid, $mountPointParameter = '', PageRepository $context = null)
    {
        $this->pageUid = (int)$uid;
        $this->mountPointParameter = trim($mountPointParameter);
        if ($context === null) {
            if (isset($GLOBALS['TSFE']) && is_object($GLOBALS['TSFE']) && is_object($GLOBALS['TSFE']->sys_page)) {
                $this->pageContext = $GLOBALS['TSFE']->sys_page;
            } else {
                $this->pageContext = GeneralUtility::makeInstance(\TYPO3\CMS\Frontend\Page\PageRepository::class);
            }
        } else {
            $this->pageContext = $context;
        }
        $this->initializeObject();
    }

    /**
     * Initialize a state to work with
     *
     * @throws \RuntimeException
     * @return void
     */
    protected function initializeObject()
    {
        $this->languageUid = (int)$this->pageContext->sys_language_uid;
        $this->workspaceUid = (int)$this->pageContext->versioningWorkspaceId;
        $this->versionPreview = $this->pageContext->versioningPreview;
        if ($this->mountPointParameter !== '') {
            if (!$GLOBALS['TYPO3_CONF_VARS']['FE']['enable_mount_pids']) {
                throw new \RuntimeException('Mount-Point Pages are disabled for this installation. Cannot resolve a Rootline for a page with Mount-Points', 1343462896);
            } else {
                $this->parseMountPointParameter();
            }
        }
        if (self::$cache === null) {
            self::$cache = GeneralUtility::makeInstance(\TYPO3\CMS\Core\Cache\CacheManager::class)->getCache('cache_rootline');
        }
        self::$rootlineFields = array_merge(self::$rootlineFields, GeneralUtility::trimExplode(',', $GLOBALS['TYPO3_CONF_VARS']['FE']['addRootLineFields'], true));
        self::$rootlineFields = array_unique(self::$rootlineFields);
        $this->databaseConnection = $GLOBALS['TYPO3_DB'];

        $this->cacheIdentifier = $this->getCacheIdentifier();
    }

    /**
     * Purges all rootline caches.
     *
     * Note: This function is intended to be used in unit tests only.
     *
     * @return void
     */
    public static function purgeCaches()
    {
        self::$localCache = array();
        self::$pageRecordCache = array();
    }

    /**
     * Constructs the cache Identifier
     *
     * @param int $otherUid
     * @return string
     */
    public function getCacheIdentifier($otherUid = null)
    {
        $mountPointParameter = (string)$this->mountPointParameter;
        if ($mountPointParameter !== '' && strpos($mountPointParameter, ',') !== false) {
            $mountPointParameter = str_replace(',', '__', $mountPointParameter);
        }

        return implode('_', array(
            $otherUid !== null ? (int)$otherUid : $this->pageUid,
            $mountPointParameter,
            $this->languageUid,
            $this->workspaceUid,
            $this->versionPreview ? 1 : 0
        ));
    }

    /**
     * Returns the actual rootline
     *
     * @return array
     */
    public function get()
    {
        if (!isset(static::$localCache[$this->cacheIdentifier])) {
            $entry = static::$cache->get($this->cacheIdentifier);
            if (!$entry) {
                $this->generateRootlineCache();
            } else {
                static::$localCache[$this->cacheIdentifier] = $entry;
                $depth = count($entry);
                // Populate the root-lines for parent pages as well
                // since they are part of the current root-line
                while ($depth > 1) {
                    --$depth;
                    $parentCacheIdentifier = $this->getCacheIdentifier($entry[$depth - 1]['uid']);
                    // Abort if the root-line of the parent page is
                    // already in the local cache data
                    if (isset(static::$localCache[$parentCacheIdentifier])) {
                        break;
                    }
                    // Behaves similar to array_shift(), but preserves
                    // the array keys - which contain the page ids here
                    $entry = array_slice($entry, 1, null, true);
                    static::$localCache[$parentCacheIdentifier] = $entry;
                }
            }
        }
        return static::$localCache[$this->cacheIdentifier];
    }

    /**
     * Queries the database for the page record and returns it.
     *
     * @param int $uid Page id
     * @throws \RuntimeException
     * @return array
     */
    protected function getRecordArray($uid)
    {
        $currentCacheIdentifier = $this->getCacheIdentifier($uid);
        if (!isset(self::$pageRecordCache[$currentCacheIdentifier])) {
            $row = $this->databaseConnection->exec_SELECTgetSingleRow(implode(',', self::$rootlineFields), 'pages', 'uid = ' . (int)$uid . ' AND pages.deleted = 0 AND pages.doktype <> ' . PageRepository::DOKTYPE_RECYCLER);
            if (empty($row)) {
                throw new \RuntimeException('Could not fetch page data for uid ' . $uid . '.', 1343589451);
            }
            $this->pageContext->versionOL('pages', $row, false, true);
            $this->pageContext->fixVersioningPid('pages', $row);
            if (is_array($row)) {
                if ($this->languageUid > 0) {
                    $row = $this->pageContext->getPageOverlay($row, $this->languageUid);
                }
                $row = $this->enrichWithRelationFields(isset($row['_PAGES_OVERLAY_UID']) ? $row['_PAGES_OVERLAY_UID'] : $uid, $row);
                self::$pageRecordCache[$currentCacheIdentifier] = $row;
            }
        }
        if (!is_array(self::$pageRecordCache[$currentCacheIdentifier])) {
            throw new \RuntimeException('Broken rootline. Could not resolve page with uid ' . $uid . '.', 1343464101);
        }
        return self::$pageRecordCache[$currentCacheIdentifier];
    }

    /**
     * Resolve relations as defined in TCA and add them to the provided $pageRecord array.
     *
     * @param int $uid Page id
     * @param array $pageRecord Array with page data to add relation data to.
     * @throws \RuntimeException
     * @return array $pageRecord with additional relations
     */
    protected function enrichWithRelationFields($uid, array $pageRecord)
    {
        $pageOverlayFields = GeneralUtility::trimExplode(',', $GLOBALS['TYPO3_CONF_VARS']['FE']['pageOverlayFields']);
        foreach ($GLOBALS['TCA']['pages']['columns'] as $column => $configuration) {
            if ($this->columnHasRelationToResolve($configuration)) {
                $configuration = $configuration['config'];
                if ($configuration['MM']) {
                    /** @var $loadDBGroup \TYPO3\CMS\Core\Database\RelationHandler */
                    $loadDBGroup = GeneralUtility::makeInstance(\TYPO3\CMS\Core\Database\RelationHandler::class);
                    $loadDBGroup->start(
                        $pageRecord[$column],
                        isset($configuration['allowed']) ? $configuration['allowed'] : $configuration['foreign_table'],
                        $configuration['MM'],
                        $uid,
                        'pages',
                        $configuration
                    );
                    $relatedUids = isset($loadDBGroup->tableArray[$configuration['foreign_table']])
                        ? $loadDBGroup->tableArray[$configuration['foreign_table']]
                        : array();
                } else {
                    $columnIsOverlaid = in_array($column, $pageOverlayFields, true);
                    $table = $configuration['foreign_table'];
                    $field = $configuration['foreign_field'];
                    $whereClauseParts = array($field . ' = ' . (int)($columnIsOverlaid ? $uid : $pageRecord['uid']));
                    if (isset($configuration['foreign_match_fields']) && is_array($configuration['foreign_match_fields'])) {
                        foreach ($configuration['foreign_match_fields'] as $field => $value) {
                            $whereClauseParts[] = $field . ' = ' . $this->databaseConnection->fullQuoteStr($value, $table);
                        }
                    }
                    if (isset($configuration['foreign_table_field'])) {
                        if ((int)$this->languageUid > 0 && $columnIsOverlaid) {
                            $whereClauseParts[] = trim($configuration['foreign_table_field']) . ' = \'pages_language_overlay\'';
                        } else {
                            $whereClauseParts[] = trim($configuration['foreign_table_field']) . ' = \'pages\'';
                        }
                    }
                    if (isset($GLOBALS['TCA'][$table]['ctrl']['enablecolumns']['disabled'])) {
                        $whereClauseParts[] = $table . '.' . $GLOBALS['TCA'][$table]['ctrl']['enablecolumns']['disabled'] . ' = 0';
                    }
                    $whereClause = implode(' AND ', $whereClauseParts);
                    $whereClause .= $this->pageContext->deleteClause($table);
                    $orderBy = isset($configuration['foreign_sortby']) ? $configuration['foreign_sortby'] : '';
                    $rows = $this->databaseConnection->exec_SELECTgetRows('uid', $table, $whereClause, '', $orderBy);
                    if (!is_array($rows)) {
                        throw new \RuntimeException('Could to resolve related records for page ' . $uid . ' and foreign_table ' . htmlspecialchars($configuration['foreign_table']), 1343589452);
                    }
                    $relatedUids = array();
                    foreach ($rows as $row) {
                        $relatedUids[] = $row['uid'];
                    }
                }
                $pageRecord[$column] = implode(',', $relatedUids);
            }
        }
        return $pageRecord;
    }

    /**
     * Checks whether the TCA Configuration array of a column
     * describes a relation which is not stored as CSV in the record
     *
     * @param array $configuration TCA configuration to check
     * @return bool TRUE, if it describes a non-CSV relation
     */
    protected function columnHasRelationToResolve(array $configuration)
    {
        $configuration = $configuration['config'];
        if (!empty($configuration['MM']) && !empty($configuration['type']) && in_array($configuration['type'], array('select', 'inline', 'group'))) {
            return true;
        }
        if (!empty($configuration['foreign_field']) && !empty($configuration['type']) && in_array($configuration['type'], array('select', 'inline'))) {
            return true;
        }
        return false;
    }

    /**
     * Actual function to generate the rootline and cache it
     *
     * @throws \RuntimeException
     * @return void
     */
    protected function generateRootlineCache()
    {
        $page = $this->getRecordArray($this->pageUid);
        // If the current page is a mounted (according to the MP parameter) handle the mount-point
        if ($this->isMountedPage()) {
            $mountPoint = $this->getRecordArray($this->parsedMountPointParameters[$this->pageUid]);
            $page = $this->processMountedPage($page, $mountPoint);
            $parentUid = $mountPoint['pid'];
            // Anyhow after reaching the mount-point, we have to go up that rootline
            unset($this->parsedMountPointParameters[$this->pageUid]);
        } else {
            $parentUid = $page['pid'];
        }
        $cacheTags = array('pageId_' . $page['uid']);
        if ($parentUid > 0) {
            // Get rootline of (and including) parent page
            $mountPointParameter = !empty($this->parsedMountPointParameters) ? $this->mountPointParameter : '';
            /** @var $rootline \TYPO3\CMS\Core\Utility\RootlineUtility */
            $rootline = GeneralUtility::makeInstance(\TYPO3\CMS\Core\Utility\RootlineUtility::class, $parentUid, $mountPointParameter, $this->pageContext);
            $rootline = $rootline->get();
            // retrieve cache tags of parent rootline
            foreach ($rootline as $entry) {
                $cacheTags[] = 'pageId_' . $entry['uid'];
                if ($entry['uid'] == $this->pageUid) {
                    throw new \RuntimeException('Circular connection in rootline for page with uid ' . $this->pageUid . ' found. Check your mountpoint configuration.', 1343464103);
                }
            }
        } else {
            $rootline = array();
        }
        array_push($rootline, $page);
        krsort($rootline);
        static::$cache->set($this->cacheIdentifier, $rootline, $cacheTags);
        static::$localCache[$this->cacheIdentifier] = $rootline;
    }

    /**
     * Checks whether the current Page is a Mounted Page
     * (according to the MP-URL-Parameter)
     *
     * @return bool
     */
    public function isMountedPage()
    {
        return in_array($this->pageUid, array_keys($this->parsedMountPointParameters));
    }

    /**
     * Enhances with mount point information or replaces the node if needed
     *
     * @param array $mountedPageData page record array of mounted page
     * @param array $mountPointPageData page record array of mount point page
     * @throws \RuntimeException
     * @return array
     */
    protected function processMountedPage(array $mountedPageData, array $mountPointPageData)
    {
        if ($mountPointPageData['mount_pid'] != $mountedPageData['uid']) {
            throw new \RuntimeException('Broken rootline. Mountpoint parameter does not match the actual rootline. mount_pid (' . $mountPointPageData['mount_pid'] . ') does not match page uid (' . $mountedPageData['uid'] . ').', 1343464100);
        }
        // Current page replaces the original mount-page
        if ($mountPointPageData['mount_pid_ol']) {
            $mountedPageData['_MOUNT_OL'] = true;
            $mountedPageData['_MOUNT_PAGE'] = array(
                'uid' => $mountPointPageData['uid'],
                'pid' => $mountPointPageData['pid'],
                'title' => $mountPointPageData['title']
            );
        } else {
            // The mount-page is not replaced, the mount-page itself has to be used
            $mountedPageData = $mountPointPageData;
        }
        $mountedPageData['_MOUNTED_FROM'] = $this->pageUid;
        $mountedPageData['_MP_PARAM'] = $this->pageUid . '-' . $mountPointPageData['uid'];
        return $mountedPageData;
    }

    /**
     * Parse the MountPoint Parameters
     * Splits the MP-Param via "," for several nested mountpoints
     * and afterwords registers the mountpoint configurations
     *
     * @return void
     */
    protected function parseMountPointParameter()
    {
        $mountPoints = GeneralUtility::trimExplode(',', $this->mountPointParameter);
        foreach ($mountPoints as $mP) {
            list($mountedPageUid, $mountPageUid) = GeneralUtility::intExplode('-', $mP);
            $this->parsedMountPointParameters[$mountedPageUid] = $mountPageUid;
        }
    }
}
